# List of medical abbreviations

Abbreviations are used very frequently in medicine. They boost efficiency as long as they are used intelligently. The advantages of brevity should be weighed against the possibilities of obfuscation (making the communication harder for others to understand) and ambiguity (having more than one possible interpretation). Certain medical abbreviations are avoided to prevent mistakes, according to best practices (and in some cases regulatory requirements); these are flagged in the list of abbreviations used in medical prescriptions.

## Orthographic styling
### Periods (stops)

Periods (stops) are often used in styling abbreviations. Prevalent practice in medicine today is often to forgo them as unnecessary.
* Example:
** Less common: The diagnosis was C.O.P.D. [chronic obstructive pulmonary disease]
** More common: The diagnosis was COPD

### Plurals

The prevalent way to represent plurals for medical acronyms and initialisms is simply to affix a lowercase s (no apostrophe).
* Example: one OCP, two OCPs [oral contraceptive pills].

### Possessives

Possessive forms are not often needed, but can be formed using apostrophe + s. Often the writer can also recast the sentence to avoid it.
* Example:
** BP's effect on risk of MI is multifaceted.
** The effect of BP on MI risk is multifaceted.

### Arrows

Arrows may be used to indicate numerous conditions including elevation (↑), diminution (↓), and causation (→, ←).

## Pronunciation

Pronunciation follows convention outside the medical field, in which acronyms are generally pronounced as if they were a word (JAMA, SIDS), initialisms are generally pronounced as individual letters (DNA, SSRI), and abbreviations generally use the expansion (soln. = "solution", sup. = "superior"). Abbreviations of weights and measures are pronounced using the expansion of the unit (mg = "milligram") and chemical symbols using the chemical expansion (NaCl = "sodium chloride"). Some initialisms deriving from Latin may be pronounced either as letters (qid = "cue eye dee") or using the English expansion (qid = "four times a day").

## Some common medical abbreviations

Notation conventions
* This series of lists omits periods from acronyms and initialisms.
* It uses periods for certain abbreviations that traditionally often have them (mostly older Latin/Neo-Latin abbreviations). For example, both bid and b.i.d. may be found in the list.
* It generally uses the singular form of an abbreviation (not the plural) as the headword.
* This list uses significant capitalization for headwords (the abbreviations) and their expansions.
| EG abb | EG full name | Other (ver change, need to know...etc.) |
| ABG | arterial blood gas | |
| ACE | angiotensin-converting enzyme | |
| ACTH | adrenocorticotropic hormone | |
| AFVSS | Afebrile, vital signs stable | |
| ADH | antidiuretic hormone | |
| AED | automated external defibrillator | |
| AIDS | acquired immunodeficiency syndrome | |
| ALP | alkaline phosphatase | |
| ALT | alanine aminotransferase | old version is SGPT |
| ASA | acetylsalicylic acid | aspirin |
| AST | aspartate aminotransferase | old version is SGOT |
| ATP | adenosine triphosphate | |
| BCG | bacille Calmette-Guérin | |
| bd, bid | 2 times a day | |
| BIBA | brought in by ambulance | |
| BIBP, BIBPD | brought in by police | |
| BLS | basic life support | |
| BMR | basal metabolic rate | |
| BP | blood pressure | |
| BPAD | bipolar affective disorder | |
| BPD | borderline personality disorder | Often incorrectly used for bipolar disorder (BPAD is preferred) |
| BSA | body surface area | |
| BR | bedside rounds | |
| BUN | blood urea nitrogen | |
| C | Celsius; centigrade; complement | |
| Ca | calcium | |
| CAMP, cAMP | cyclic adenosine monophosphate | |
| CBC | complete blood count | |
| CDC | Centers for Disease Control and Prevention | |
| cGy | centigray | |
| Ci | curie | |
| CK | creatine kinase | |
| Cl | chloride; chlorine | |
| cm | centimeter(s)/centimetre(s) | |
| CNS | central nervous system | |
| CO2 | carbon dioxide | |
| COPD | chronic obstructive pulmonary disease | |
| CPK | creatine phosphokinase | |
| CPK-MB | creatine phosphokinase muscle bandisoenzyme | |
| CPR | cardiopulmonary resuscitation | |
| CSF | cerebrospinal fluid | |
| CT | computed tomography | |
| Cu | cubic | |
| D & C | dilation and curettage | |
| dL | deciliter(s)/decilitre(s) | 1 dL = 100 mL |
| DNA | deoxyribonucleic acid | |
| DTP | diphtheria-tetanus-pertussis(toxoids/vaccine) | |
| D/W | dextrose in water | |
| ECF | extracellular fluid | |
| ECG | electrocardiogram | |
| EEG | electroencephalogram | |
| EGD | esophagogastroduodenoscopy | |
| ENT | ear nose and throat | |
| ERCP | endoscopic retrograde cholangiopancreatography | |
| ESR | erythrocyte sedimentation rate | |
| F | Fahrenheit | |
| FDA | U.S. Food and Drug Administration | |
| Ft | foot; feet | measure unit |
| FUO | fever of unknown origin | |
| G, g | gram(s) | |
| GFR | glomerular filtration rate | |
| GI | gastrointestinal | |
| GVHD | graft-versus-host disease | |
| G6PD | glucose-6-phosphate dehydrogenase | |
| GU | genitourinary | |
| Gy | gray | |
| H, h, hr | hour(s) | '/24' is generally used in some regions. |
| Hb | hemoglobin | |
| HCl | hydrochloric acid; hydrochloride | |
| HCO3 | bicarbonate | |
| Hct | hematocrit | |
| Hg | mercury | |
| HIPAA | Health Insurance Portability and Accountability Act | |
| HIV | human immunodeficiency virus | |
| HLA | human leukocyte antigen | |
| HMG-CoA | hydroxymethyl glutaryl coenzyme A | |
| hs | at bedtime | |
| Hz | hertz | cycles/second unit |
| ICF | intracellular fluid | |
| ICU | intensive care unit | |
| IgA | etc. immunoglobulin A | |
| IL | interleukin | |
| IM | intramuscular(ly) | |
| INR | international normalized ratio | |
| IPPB | intermittent positive pressure breathing | |
| IU | international unit | |
| IV | intravenous(ly) | |
| IVU | intravenous urography | |
| K | potassium | |
| kcal | kilocalorie(s) | mean food calorie |
| kg | kilogram(s) | |
| L | liter(s)/litre(s) | |
| lb | pound(s) | |
| LDH | lactic dehydrogenase | |
| LDLc | low-density lipoprotein cholesterol | |
| M | molar | |
| m | meter(s)/metre(s) | |
| mane | in the morning | |
| mc | micro- | required in some regions to avoid the confusion of 'μ' with 'm' ('milli-'). |
| MCH | mean corpuscular hemoglobin | |
| MCHC | mean corpuscular hemoglobin concentration | |
| mCi | millicurie | |
| MCV | mean corpuscular volume | |
| mEq | Milliequivalent | |
| midi | midday |
| Mg | magnesium | |
| mg | milligram(s) | |
| MI | myocardial infarction | |
| MIC | minimum inhibitory concentration | |
| min(s) | minute(s) | '/60' is used in some regions. |
| mIU | milli-international unit | |
| mL, ml | milliliter(s)/millilitre(s) | |
| mm | millimeter(s)/millimetre(s) | |
| mmol | millimole(s) | |
| mo | month | '/12' is used in some regions. |
| mol | wt molecular weight | |
| mOsm | milliosmole(s) | |
| MRI | magnetic resonance imaging | |
| N | nitrogen; normal | unit to measure strength of solution |
| Na | sodium | |
| NaCl | sodium chloride | |
| NAEON | no adverse events overnight | |
| ng | nanogram | billionth of a gram; also known as millimicrogram |
| nm | nanometer | billionth of a meter; also known as millimicron |
| nmol | nanomole | |
| nocte | at night | |
| Npo | nothing by mouth/nil by mouth | |
| NSAID | nonsteroidal anti-inflammatory drug | |
| O2 | oxygen | |
| OTC | over-the-counter | pharmaceuticals |
| oz | ounce(s) | |
| P | phosphorus; pressure | |
| PAco2 | alveolar carbon dioxide partial pressure | |
| Paco2 | arterial carbon dioxide partial pressure | |
| PAo2 | alveolar oxygen partial pressure | |
| Pao2 | arterial oxygen partial pressure | |
| PAS | periodic acid-Schiff | |
| Pco2 | carbon dioxide partial pressure | or tension |
| PCR | polymerase chain reaction | |
| PET | positron emission tomography | |
| pg | picogram(s) | micromicrogram |
| pH | hydrogen ion concentration | |
| PMN | polymorphonuclear leukocyte | |
| po | orally | |
| Po2 | oxygen partial pressure | or tension |
| PPD | purified protein derivative | tuberculin |
| ppm | parts per million | |
| prn | as needed | from the Latin pro re nata |
| PT | prothrombin time | |
| PTT | partial thromboplastin time | |
| q | every | |
| qid | 4 times a day | |
| RA | rheumatoid arthritis | |
| RBC | red blood cell | |
| RNA | ribonucleic acid | |
| Sao2 | arterial oxygen saturation | |
| SBE | subacute bacterial endocarditis | |
| sc | subcutaneous(ly) | |
| s/e | side-effect(s) | |
| SI | International System of Units | |
| SIDS | sudden infant death syndrome | |
| SLE | systemic lupus erythematosus | |
| soln | solution | |
| sp | species | singular |
| spp | species | plural |
| sp gr | specific gravity | |
| sq | square | |
| SSRI | selective serotonin reuptake inhibitor | |
| STS | serologic test(s) for syphilis | |
| T&A | tonsillectomy and adenoidectomy | |
| TB | tuberculosis | |
| tds | 3 times a day | tid preferred in some regions |
| TIBC | total iron-binding capacity | |
| tid | 3 times a day | tds preferred in some regions |
| TPN | total parenteral nutrition | |
| URI | upper respiratory infection | |
| URTI | upper respiratory tract infection | |
| UTI | urinary tract infection | |
| WBC | white blood cell | |
| WHO | World Health Organization | |
| WR | ward round | |
| wt | weight | |
| μ | micro-; micron | |
| μCi | microcurie | |
| μg | microgram(s) | |
| μL | microliter(s)/microlitre(s) | |
| μm | micrometer(s)/micrometre(s) | also referred to as microns |
| μmol | micromole(s) | |
| μOsm | micro-osmole(s) | |
| mμ | millimicron(s) | also referred to as nanometers/nanometres |